ZIRCONIUM SILICATE FLOUR ~ ZIRC 5 ~ 100 TO 500 GRAMS. In glazes, 4-7% zircon produces semi opaque results. Notes on use of Zirconium Silicate. Zircon stiffens the glaze and produces harder glaze surface and reduces thermal expansion more than tin as well as reacts less with colourants in the glaze than tin.
